This invention concerns an electronic device that has a circuit board on which is mounted a computation processing device and on which is formed a power supply wiring pattern for supplying electric power to this computation processing device in general, and more particularly, to an electronic device having an efficient heat radiator so that the electronic device can be made more compact.
Heretofore, entertainment devices, personal computers, and other electronic devices that employ an optical disk, such as game machines and CD, and DVD players and the like, have been constructed with a disk device that includes an optical pickup unit, a circuit board on which a CPU and image processing unit are mounted, and a cabinet made up of an upper case and lower case that houses such components. And if for example it is an entertainment device, image information and sound information recorded on an optical disk can be played by detecting it with the optical pickup unit, computation-processing it with the CPU and image processing unit, and outputting video and audio control signals to a display device, etc.
With such an electronic device, the playback of image information and sound information is greatly affected by the processing capacity of the CPU and image processing unit, so it is required that the processing capacity of the CPU and image processing unit be accelerated. When the processing capacity of the CPU and image processing unit is accelerated, the electromagnetic waves emitted from their circuit elements become stronger, and normally measures against EMI are implemented.
Specifically, if the cabinet is made of ABS resin, etc., anti-EMI measures are done by covering the circuit board that includes the CPU and image processing unit with metal shielding plates and ensuring electrical continuity between these shielding plates and the grounding pattern formed on the circuit board, which means that the circuit board is housed inside the cabinet sandwiched in between two metal shielding plates. Usually provided on the circuit board is a regulator on the power supply wiring pattern on the circuit board for stabilizing and supplying electric power to the CPU, etc. This regulator converts the difference in input and output voltages to heat and gives off heat, so a mechanism is required to allow the heat of the regulator to escape. In a circuit board covered by two shielding plates as described above, heretofore structures have been adopted in which the shielding plates are brought into contact with the regulator and the heat of the regulator is radiated away.
But as electronic devices have been made smaller, structures have come to be adopted in which a disk device including an optical pickup unit is placed directly over a shielding plate, and in order not to heat up the optical pickup unit with such a structure, this has led to the desire for a structure in which the heat of the regulator is efficiently shed without heating up the shielding plates.
It is an object of the present invention, therefore, to provide an electronic device that can efficiently radiate the heat of the regulator and promote a smaller overall size construction.
Still other objects and advantages of the invention will become clear upon review of the following detailed description in conjunction with the appended drawings.
An electronic device comprises a circuit board, on which is mounted a computation processing device on which is formed a power supply wiring pattern for supplying electric power to this computation processing device, covered by metal shielding plates, a regulator to stabilize the supplied voltage mounted on the power supply wiring pattern, and a radiator provided on the regulator positioned on the outer side of said circuit board as seen from the direction normal to the board plane of said circuit board. The heat of the regulator is emitted from a radiator positioned on the outer side of the circuit board, which enables elements that do not stand up very well to heat, such as an optical pickup unit, to be placed directly on the shielding plate.
It is thus desirable that an opening be formed in said shielding plate through which the regulator protrudes without coming into contact with said shielding plate, so that the regulator and shielding plate do not touch one another and the transmission of the heat of the regulator to the shielding plate can be securely prevented.